This project's goal is the measurement of the local cerebral blood flow (LCBF) and the local cerebral metabolic rate for glucose utilization (LCMR) glucose in the same animal using quantitative double radionuclide autoradiography. This will be accomplished by combining established techniques for the measuremtn of LCBF with radio-labeled iodoantipyrine and LCMR glucose with radio-labeled 2-deoxy-d-glucose. Iodine-123 (T 1/2 is equal to 13 hours) labedle iodoantipyrine (123-I-IAP) will be used with 14C labeled2-deoxy-D-glucose (14C-2DG). Double radionuclide autoradiography will involve a double exposure of both 123I and 14C and a subsequent single exposure of 14C after 123I has completely decayed. The 123I brain concentration can be recovered by quantitatively subtracting the exposure due to 14C. The subtracted 123I brain concentration will be used to quantitate LCBF, while the 14C brain concentration obtaaned from the second single exposure will be used to quantitate LCMR-glucose. Double radionuclide autoradiography will be validated by comparing known concentration of both 123I and 14C in brain homogenates with the concentrations obtained by subtracting exposures. Further validation will involve a double flow study using 123I-IAP and 14C labeled iodoantipyrine. Local CBF will be computed using both radionuclides and compared. Further objectives in this proposal include the simultaneous measurement of LCBF and LCMR glucose in normal animals and in experimental focal epilepsy to directly test the hypotheses that: 1. the flow metabolism couple exists in the normal animal and 2. that this couple is not disturbed by the metabolic challenge of seizures. Such a technique for the combined determination of LCBF and LCMR glucose has applicability in any pathological state where focal changes in CBF or CMR glucose occur.